Sorry I didn't see these questions before Christmas, but you should be able to find this ruler at your local quilt shop. I've also see them on ebay and saw one once here on the quilt board for sale by a member.

angiecub, I love this tree skirt and used your tute when it first came out on QB to make two of my own. Has anyone out there tried adjusting the pattern to make a larger tree skirt? My daughter wants one that is 70-72" in diameter instead of 50". I would want to add more fabric rows to each panel, but can't figure out how wide each new strip should be to increase to a 35-35" panel. Your ideas or thoughts will be greatly appreciated!